The England number 10 jersey has become the subject of fierce debate in recent months, with Ford and Owen Farrell battling it out to be Stuart Lancaster's starting fly-half. Farrell played throughout last year's Six Nations, ending the tournament as second-top scorer, but appeared to lose his grip on the position during the November internationals. After starting the defeats to New Zealand and South Africa, Farrell was replaced by Ford for the victories against Samoa and Australia. A knee injury for Farrell appears to have made Lancaster's selection somewhat easier, but Bath's Ford, who could face competition from Danny Cipriani and Stephen Myler, will be eager to make the role his own ahead of a World Cup on home soil later in the year.

France - Wesley Fofana

One of French rugby's leading lights, Fofana will undoubtedly be key to his inconsistent team's chances of lifting the Six Nations trophy for the first time since 2010. The Clermont Auvergne man has 30 caps to his name and, at 27, is the old head among the French centres, and less internationally experienced colleagues such as Alexandre Dumoulin and Gael Fickou could do worse than look to their Paris-born team-mate for inspiration.

Ireland - Robbie Henshaw

This year's Six Nations marks the first tournament since legendary centre Brian O'Driscoll hung up his boots, leaving a gaping hole in the Ireland midfield. Henshaw is among the leading candidates to fill that void long-term, with O'Driscoll himself having lent support to the 21-year-old's bid for the number 13 jersey. Time will tell whether the Connacht starlet can live up to the achievements of his illustrious mentor, but Henshaw certainly made all the right moves as he impressed in wins over South Africa and Australia in November.

Italy - Sergio Parisse

Parisse has been a staple of Italian rugby for more than a decade and, as captain, continues to prove the most influential figure in the squad. Along with Marco Bortolami (110 caps), Martin Castrogiovanni (107) and Mauro Bergamasco (100), number eight Parisse (108) forms part of a quartet of centurions who will be keen to steer Italy to their most successful tournament yet, with Jacques Brunel's men set to play three home matches this year.

Scotland - Richie and Jonny Gray

Brothers Richie and Jonny Gray have locked out the Scottish second row in recent matches, starting together at four and five respectively against Argentina, New Zealand and Tonga in November. The siblings scored a try apiece in a 41-31 victory over the South Americans, and will be hoping to maintain their run alongside each other throughout this year's tournament. Older brother Richie has amassed 42 caps since making his Scotland debut in 2010 and there can be no better mentor for 20-year-old Jonny, who is just finding his international feet after making eight senior appearances for his country.

Wales - Rhys Webb

Like the fight for England's number 10 shirt, the battle to be Wales' starting scrum-half is an intense one. Mike Phillips has long been in ownership of the position, but the emergence of Ospreys number nine Webb on the international scene has given coach Warren Gatland something of a selection headache. Webb started twice at last year's tournament and looked to be Gatland's preferred option in November, playing three of Wales' four Tests. The 26-year-old will start Wales' opener against England on Friday, but will have to be on his toes to hold off Phillips, who will be hungry to force his way back in ahead of the World Cup.